Grzegorz Kowalewski

Relationship between renal resistive index and early target organ damage in patients with never treated essential hypertension

The aim of our study was to evaluate renal resistive index (RI) value in never treated hypertensive patients in relation to ambulatory blood pressure measurement (ABPM) values and early target organ damage. The study included 318 subjects: 223 patients with never treated essential hypertension (mean age 37.1 years) and 95 normotensive healthy subjects (mean age 37.9 years). ABPM, echocardiography and carotid and renal arteries duplex color Doppler examinations were performed. RI values in patients with never treated essential hypertension were no different from the normotensive control group (0.59 ± 0.05 vs 0.59 ± 0.05; NS). In the untreated patients RI correlated significantly with 24‐h pulse pressure (r=0.234; p<0.01) and ambulatory arterial stiffness index (AASI) values (r=0.274; p<0.001), intima‐media thickness (IMT) (r=0.249; p<0.001), E′/A′ (rho= −0.279; p<0.001) and relative wall thickness (RWT; r=0.185; p<0.01). In the multivariate stepwise analysis, RI values correlated independently with carotid IMT (β=0.272; p=0.020) and 24‐h AASI values (β=0.305; p=0.009). In normotensive healthy controls, significant independent correlation between RI and carotid IMT and 24‐h AASI values were also found. Our study may indicate limited value of RI in differentiating patients with uncomplicated hypertension with healthy controls. Renal resistive values were independently correlated with carotid IMT and AASI. These may suggest that renal vascular resistance is related to two markers for cardiovascular events both in the hypertensive and normotensive subjects.

Climate-related changes during the Late Glacial and early Holocene in northern Poland, as derived from the sediments of Lake Sierzywk

Reconstruction of past climate change and ecosystem response is important to correctly assess the impacts of global warming. In this study, we provide a paleoenvironmental record of in-lake and catchment changes in northern Poland during the Late Glacial and early Holocene using various biotic proxies (pollen, macrofossils and Cladocera) preserved in the lake sedimentary record. Chronology was derived from palynological correlation with a well-dated pollen sequence from nearby-lying Lake Ostrowite and some well-dated events of vegetation history in Central Europe. Pollen analysis provided information on regional climate change affecting vegetation dynamics, whereas macrofossils supplied substantial information on the response of local flora and fauna to climatic, geomorphological and limnological changes. Data were supplemented by analysis of Cladocera remains, which are of special importance because of their quick response to changes in trophic conditions and climate (especially temperature). The bottom of the sediment core reflects an initial stage of the lake formed during the late Alleröd. The Younger Dryas cooling apparently resulted in forest recession and presence of cold tolerant Cladocera species. Due to amelioration of climate at the end of the Younger Dryas and melting of ice, the lake deepened. The beginning of the Holocene was characterised by forest shrinkage and induced clear changes in local flora and fauna communities. The regional vegetation development deduced from the lake’s core is generally consistent with the vegetation history of central Europe. Due to the location of the site near the seashore (oceanic climate and western wind), signals of warming came earlier than inland and in eastern Poland.

Hydrological changes in the Rzecin peatland (Puszcza Notecka, Poland) induced by anthropogenic factors: Implications for mire development and carbon sequestration:

Wetlands are very vulnerable ecosystems and sensitive to changes in the ground water table. For the last few thousand years, hydrological balance has also been influenced by human activity. To improve their cropping features, drainage activity and fertilizing were applied. The drainage process led to an abrupt change of environment, the replacement of plant communities and the entire ecosystem. The problem of carbon sequestration is very important nowadays. A higher accumulation rate is related to higher carbon accumulation, but the intensity of carbon sequestration depends on the type of mire, habitat, and climatic zone. The main aim of this article was an examination of the changes in poor-fen ecosystem during the last 200 years in relation to natural and anthropogenic factors, using paleoecological methods (pollen and macrofossils). The second aim was a detailed investigation of the sedimentary record to aid our understanding of carbon sequestration in the poor fen of temperate zone. This case study shows that fens in temperate zones, in comparison with boreal ones, show higher carbon accumulation rates which have been especially intensive over the last few decades. To reconstruct vegetation changes, detailed palynological and macrofossil analyses were done. A 200-year history of the mire revealed that it was influenced by human activity to much degree. However, despite the nearby settlement and building of the drainage ditch, the precious species and plant communities still occur.

Disentangling natural and anthropogenic drivers of changes in a shallow lake using palaeolimnology and historical archives

Shallow lakes are susceptible to catastrophic regime shifts characterised by the presence or absence or macrophytes. However, the long-term controls on macrophyte succession in shallow lakes are incompletely understood. To investigate this, we analysed multiple sediment proxies in Lake Rotcze (Eastern Poland), a small, shallow and densely macrophyte-covered lake to (1) reconstruct the ‘reference conditions’ (sensu WFD) and development of the lake in recent centuries, (2) compare historical evidence with the sedimentary record, and (3) identify the natural and anthropogenic drivers of macrophyte succession. Before the twentieth century, conditions in the lake may be referred to as ‘reference conditions’. Subsequently forest clearance in the catchment resulted in lower water transparency, but concurrent catchment drainage lowered water levels and increased macrophyte development. Since 1950 elevated nutrient supply and climatically driven increases in water levels led to the deterioration of water transparency and partial macrophyte withdrawal. At the end of the twentieth century lake-level drawdown led to low phytoplankton biomass and clear water creating a novel ecosystem where macrophytes invade the whole lake. These patterns suggest that both natural and anthropogenically induced water level fluctuations have been critical drivers of macrophyte development.

Over 200 years of drainage practices and lake level drawdown in the Uściwierskie Lowering (Łęczna-Włodawa Lakeland)

Abstract Meliorations of the Łęczna-Włodawa Lakeland have considerably determined its water relations within the last more than 200 years. The analysis of the map by Anton Mayer von Heldensfeld, so far not applied in studies on the drainage network of this lakeland, executed in the years 1801-04, revealed the drainage of the Uściwierskie Lowering already at the turn of the 18th and 19th century. This shifts the commencement of strong anthropogenic impact on this area to a considerably earlier period than was previously assumed. The lakes subject to analysis (Rotcze, Uściwierz, Bikcze, and Lakes Piaseczno and Łukie neighbouring with the Lowering) were incorporated into the drainage system in various periods. Such incorporation of a water body involved water level drawdown. The water level decreased first in Lake Bikcze, and the latest in Lake Rotcze. More detailed information on changes in the water level in the lakes of the Uściwierskie Lowering since 1882 was obtained based on calculation and on comparison with current data of measurements conducted by Rostworowski. The analysis revealed that the water level in Lakes Bikcze and Piaseczno, although fluctuating, has not changed within the last 130 years, whereas the water level in Lake Uściwierz decreased by 33 cm, and in Lake Rotcze by 90 cm.

Changes in Lake Rotcze catchment over the last 200 years: implications for lake development reconstruction

Abstract Based on archival cartographic sources, teledetection materials, and research results in the scope of history and environmental sciences, changes occurring in the catchment of Lake Rotcze and its close vicinity over the last two hundred years were analysed. The area of the catchment is dominated by moderately fertile minerogenic soils on which forest assemblages developed (poor hornbeamoak forest Tilio-Carpinetum and thermophilous oak forest Potentillo albae-Quercetum). The first trace of anthropopressure was a clearing at the southern shore of the lake, for agricultural use, established not later than at the turn of the 17th and 18th century. The forests were almost completely cleared in the first quarter of the 20th century, and transformed into cultivated land of the village of Grabniak. A large fragment of the catchment is occupied by peatlands, constituting the final stage of lake-peatland succession developed in the former bay of fossil Lake Uściwierskie of which Lake Rotcze constitutes the remains. During the 20th century, the peatlands were intensively drained. This resulted in their overdrying, and growing over with bushes and marshy forests. In the 20th century, Grabniak was an agricultural village. Over the last 25 years, it has turned into a recreation resort. The relatively short agricultural and settlement activity in the lake catchment, in comparison with other parts of Poland, makes the lake appropriate for palaeolimnological reconstruction in terms of looking for reference conditions (sensu WFD).

Shoreline and surface area changes induced by floating islands in peatland lakes (Tuchola Pinewood Forest, Poland)

Shoreline and surface area changes induced by floating islands in peatland lakes (Tuchola Pinewood Forest, Poland) Multitemporal aerial photography and topographic maps were applied to investigate shoreline and surface area changes induced by floating islands in three small (area < 1 ha) peatland lakes in the Tuchola Forest. The observation period covers the last 60 years (1951-2011). Shorelines of peatland lakes are stable, unless parts of them detach as floating mats and become floating islands which could have migrated sporadically in the past. Currently, they are rooted permanently to the mat (Dury I and Dury V Lakes) or float loose (Kozie Lake). In the observation period, movement of the islands and closing of lake bays due to overgrowing were the main reasons of shoreline changes. Due to low resolution of old aerial photographs, other changes are not decipherable and can be treated as negligible. Therefore, no reasonable conclusions can be drawn regarding the actual floating mat encroachment during the last 60 years, and the rate of lake shrinking, based of aerial photographs.

Towards a more precisely defined macrophyte-dominated regime: the recent history of a shallow lake in Eastern Poland

Archived data and sedimentary macrofossil records of vegetation and invertebrates deposited in a 60-cm long sediment core were analysed to examine if macrophyte dominance was a permanent feature of the recent history of lowland Lake Kleszczów. For the last several centuries, the lake has not been dominated by phytoplankton but by floating-leaved vegetation at strongly reduced water level. Starting from the mid-nineteenth century, probably as a result of climate fluctuations, vegetation switched at first into submerged angiosperms, and then, in the second half of twentieth century, towards charophytes. Within charophytes there were switches between Chara globularis and C. vulgaris communities, depending on lake productivity or hydrological stress. No symptoms were detected of a switch to a turbid regime as a result of potential internal supply of phosphorus from sediments covered with a dense carpet of charophytes. Our study shows that within a longer period with clear water, the community of macro-vegetation can be highly dynamic. It can be represented by various types of vegetation as a response to different productivity levels and/or hydrological stress, largely determining the composition of other hydrobionts and course of various processes, and as a consequence, the functioning of the ecosystem and its resilience.